PhD positions physics, chemistry, or engineering

PhD positions at the
Max Planck Institute for Polymer Research

The Max Planck Institute for Polymer Research (MPI-P) ranks among the top research centers in the field of polymer and interface science world-wide. In the department ‘Physics at Interfaces‘ we investigate wetting of nanostructured and super liquid repellent surfaces. Our general aim is to derive quantitative descriptions of soft matter interfacial phenomena. The methods we use include laser scanning confocal microscopy, high speed video microscopy, scanning probe techniques, light and X-ray scattering.

We are welcoming applications for 7 PhD positions for a three-year program (salary according to public service salary scale TVÖD E13, 50 %). The positions are funded within the excellence initiative by the European Union, ERC advanced grant "SuPro", the innovative training network (LubISS) and the collaborative research center of the German Science Foundation (SFB 1194)
Within the intimately linked projects we plan to investigate:

Advanced optical microscopy to quantify the dynamics at the contact line between a drop and the surface

What we expect
Potential candidates must have an excellent Master (or equivalent) in physics, chemistry, or engineering. Beyond the passion for and experience in research, we expect good language and communication skills in English, flexibility, focused research and the readiness to take
the extra step of an interdisciplinary approach towards a PhD. Programming skills and knowledge in Optics is required in many of the projects.

What we offer
We offer excellent training opportunities in a highly collaborative research environment including physicists, chemists, engineers and material scientists. We provide a broad range of experimental methods, techniques, and specialized courses. Experienced technical staff is available to aid smooth adaptation to the high level instruments. The institute combines all the necessary specialized expertise from the creative design of new materials, their synthesis, physical characterization and theoretical understanding. Many outstanding short and long-term visitors are staying at MPIP.

For application, please submit
One motivation letter, which states your interests and why you want to become part of our team, which project you choose and why you think you would fit into this project. A curriculum vitae, your degree certificates (including Abitur, or equivalent), an abstract (maximum 3 pages) of your diploma or master thesis and the names and contact details of two potential referees. Interested candidates should submit their application containing the above mentioned documents in one PDF file to vollmerd@mpip-mainz.mpg.de.
The Max Planck Society intends to increase its proportion of female employees and expressly encourages women to apply. Applicants with disabilities are preferred if equally qualified.

1.

Advanced optical microscopy to quantify the dynamics at the contact line between a drop and the surface

The sliding of drops along solid surfaces is a fundamental process and can be observed everyday life such as driving a car in rain. Here drops are driven by the wind stream until finally they are rinsed off the front window. Recently, we have built up a device to measure the "sticking forces" of liquid drops on surfaces.

Within the here announced PhD thesis, the device should be combined with a high resolution and a high speed optical microscope. The goal of the thesis is to understand how a pinned drop that starts moving. The shape of the liquid contact line should be correlated with the generated forces on the drop. We aim to quantitatively analyze and theoretically describe liquids on homogeneous, structured and heterogeneous surfaces.

2.

Confocal microscopy to study dynamic solid-liquid-gas contact lines

The spreading of a liquid on a solid surface is one of the fundamental processes in everydays life. It is relevant for many industrial applications. Despite the significance, processes at the moving contact line are far from being understood. One reason for our poor understanding is a lack of techniques which have the required spacial and time resolution. The goal of the project is to modify an existing confocal microscope so that the movement of an advancing and receding contact line can be imaged. Time and special resolution should be improved as much as possible. Then the movement of contact line of pure and complex liquids on homogeneous, structured and heterogeneous surfaces will be imaged and quantitatively analyzed.

3.

Monitoring icing and deicing on
(micro)structured surfaces

Ice accretion causes malfunction and breakdown of wind power turbines, antennas and power lines. De-icing causes high environmental costs due to the consumed energy and chemicals. Still, icing and de-icing of surfaces is poorly understood. We lack microscopic information of the underlying processes close to the surface. We expect that space and time resolved information combined with the information on the stickiness of ice to the surface will foster our understanding of icing and deicing of surfaces, on cracks formation and propagation and on rupturing of surfaces.

The aim of this PhD thesis is to study the efficiency of soft and hard micro-structured surface for anti-icing applications. The successful candidate will investigate where ice nucleates and how it grows? Does a structure fail during icing or de-icing? Where and how do cracks form and propagate? To gain the required space and time-resolved information, currently, we are setting up a homebuilt laser scanning confocal microscopy that is accompanied with an icing chamber. The candidate is expected to further develop the setup in team work, including the construction of an improved icing chamber that permits to work at temperatures down to -20 °C. Furthermore, the candidate will be in charge of combining the setup with a homebuilt device to measure the adhesion force.

The PhD student will be part of the European innovative training network on "Lubricant Impregnated Slippery Surfaces" and closely interact with the other PhD students within this network as within our group. Lubricant impregnated surfaces are proposed as novel anti-icing surfaces. In close cooperation with chemists and material scientists, the candidate can also suggest or design surfaces with different surface properties.

The position requires:

Computer and mechanical engineering skills to further develop the setup

4.

Visualization and analysis of two-phase flow:

Textured substrates which are infiltrated by a lubricant form a new class of functional surfaces, called slippery surfaces. The texture is key for capillary forces to retain the lubricant in place. Slippery surfaces can repel almost all types of liquids. However, moving liquid drops (for example water) are surrounded by an annular wetting ridge, which can cause transport of lubricant (for example an oil) with the moving liquids. The same "problem" shows up if a water film is flowing over the lubricating fluid.

The aim of this PhD thesis is to understanding the interplay among the physical- and chemical interactions between the solid surface topography, the lubricating film and the liquid under static and flow conditions. To gain insight into the underlying mechanisms, the candidate will apply laser scanning confocal microscopy. This allows visualizing the sliding liquid, the lubricant, and the textured substrate with a spatial resolution of a few hundred nanometers at a line frequency of 8 kHz. The flow field can be visualized by adding tracer particles. The candidate will investigate microstructured surfaces impregnated by Newtonian liquids or swollen gels.

The PhD student will be part of the European innovative training network on "Lubricant Impregnated Slippery Surfaces" and closely interact with the other PhD students within this network as within our group. In close cooperation with chemists and material scientists, the candidate can also suggest or design surfaces with different chemical affinity of the lubricant to the surface.

Currently, we are welcoming applications for 1 PhD position for a three-year structured program. The positions are funded by the German Science Foundation through the SFB 1194.

5.

Merging of drops of partially miscible liquids

Project description
In recent years the merging of two identical drops has attracted an increasing scientific interest, because of its relevance in printing technology. Much less is known on the merging of drops of different liquids, despite potential application like modern printing or lab on a chip techniques. In this project we focus on merging of drops of different liquids. Especially we ask how parameters like miscibility, contrast in viscosity, differences in surface tension, etc., influence the dynamics of drop merging. These questions should be answered, e.g., with optical observation of the merging process under well-defined environmental conditions.

Your profile
The ideal candidate has a strong background in several of the following fields: Hydrodynamics (e.g. the laminar to turbulent transition or surface tension effects), experiment design, thermodynamics (e.g. multicomponent systems, mixing kinetics, and phase separation), optics (e.g. imaging), and computer assisted control of experiments and image analysis (this implies programming in Matlab or similar programming languages). Good communication skills in spoken and in written English are essential.

If you are interested in this position please send your application (including a letter of motivation, CV, relevant certificates and the names and contact details of two referees) to Dr. Günter Auernhammer (auhammer@mpip-mainz.mpg.de) via email (as one single PDF file) or regular mail (Max Planck Institute for Polymer Research, Dr. Günter Auernhammer, Ackermannweg 10, 55128 Mainz, Germany).

Currently, we are welcoming applications for 1 PhD position for a three-year structured program. The positions are funded by the German Science Foundation through the SFB 1194.

6.

Confocal measurement of flow profiles close to moving contact lines

Project description The wetting and dewetting dynamics of aqueous solutions and liquid mixtures is an essential part of many processes; ranging from printing and coating over pesticide distribution to cleaning processes. The multi-component nature of these systems is far beyond existing models and a quantitative modelling is still lacking. The aim of this project gain insight in the governing mechanisms of the wetting and dewetting of multi-component system. A major step in this direction is measuring the flow profile close to advancing and receding contact lines with high temporal and spatial resolution. By further developing an existing setup of a confocal microscope, the successful candidate should implement and exploit a particles tracking velocimetry scheme.

Your profile
The ideal candidate has a strong background in several of the following fields: Hydrodynamics (especially low Reynolds number flows and lubrication modelling), thermodynamics (especially adsorption equilibria and describing non-equilibrium situations), optics (especially design and alignment of laser optical systems), computer assisted experiment control and data analysis (this implies programming in Labview and Matlab or similar programming languages). Good communication skills in spoken and in written English are essential.